stairway lighting.

I have bought a house which has a single switch at the bottom of the
staircase and a double switch at the top on the landing. On of the
switches in the landing switch operates the landing lights (there are
two bulbs) the other a light in a bedroom.(Oddly, there is no switch in
the bedroom itself)
When I switch on the light in the stairs then I can switch the landing
lights on and off using the switch upstairs. However when the stairs
switch is off and I turn on the switch upstairs nothing happens.
The switches have common, L1 and L2 and the wires are red and black.
The earth is connected to the inside of the back box.
I have tried different combinations but can't seem to find one which
will allow me to turn the landing lights on and off when the stairs
switch is off.
Any help much appreciated.

Alas, you can't achieve what you want, unless the upstairs and downstairs
switches are connected by a 3-core (+earth) cable.
The thread here "New wire colours for 2 way switch" may help - esp Dave
Plowman's sketch.

LOL. Yes - as it could also be with a number (3, to be precise) of single
core (+earth) cables. But what would be the point? The OP's situation was
seen regularly many years ago (2 switches in series - regardless of the fact
that each may be a 2-way). I wonder if the existing cables are rubber
insulated.... :-)

If all you have is twin and earth cable, I suppose.. It must also depend
on the physical layout such as where the supply is picked up, where it
next goes to and where the switches and the lamp fitting are. I've seen
it done that way, with just a twin and earth between switches, using one
core to link the L1 and the other to link the L2. Obviously, there were
other cables in addition ;)

Are there three wires (plus earth) going to the downstairs switch and to
the switch on the landing that controls the landing lights?
How many cables are going into each box? Is there a link wire between
the two switches on the landing? Do any of the black wires have a piece
of red sleeving over them?

There are 2 red and 1 black in the downstairs switch and the same
upstairs I think. (I'll look when I get home and post a complete
description. This is my first time on here and I wasn't sure anyine
would bother to reply - now I know there are actually people willing to
help I'll give a fuller explanation later. Thanks for replying - I will
be back!

There are 2 red and 1 black in the downstairs switch and the same
upstairs I think.
### Ah - there is hope then. Could be as simple as downstairs switch not
making contact in one position or t'other....

I've given here a diagram which shows he wiring system.
To reitereate the problem: If the switch in the stairs is on the switch
on the landing works fine. If the switch in the stairs is off then the
switch on the landing does nothing.
All I want is that the switch on the landing works independently -
whether the switch in the stairs is on or not.
The diagram can be found on my webspace here:

I've given here a diagram which shows he wiring system.
To reitereate the problem: If the switch in the stairs is on the switch
on the landing works fine. If the switch in the stairs is off then the
switch on the landing does nothing.
All I want is that the switch on the landing works independently -
whether the switch in the stairs is on or not.
The diagram can be found on my webspace here:

http://peverett.pwp.blueyonder.co.uk/Switches.PNG
That is so spooky...
1. I assume the switch upstairs you've labelled "bedroom" is nothing to
do with it. But it looks weird...
2 My instinct is to swap the top and bottom left wires in the switch
marked "stairs" - assuming the black is "common", and is same wire as you've
shown connected to "common" upstairs.
3. To help get your head round all this, just remember that your problem
is symmetrical - by which I mean that the bottom switch works if top switch
is "on", just as top works if bottom is on. Not a lot of people realise
this.... :-)
4 If you isolate completely before trying anything, you should be safe.
It appears that all wires in the switches are (potentially) live (excepting
earth, obviously). You've no neutrals to confuse things. So with a
following wind, you may survive some experimentation, and the worst outcome
is merely a blown trip-switch or fuse.
Do report back. And make sure someone's with you when you try stuff out, so
he can report back if you don't make it....
(sorry - silly joke - but seriously, don't try this alone....)

There are a large number of possibilities:
Here's one:
Let's say that a permanent live is connected to the common terminal on
the stairs switch.
The other two wires go to the landing switch, say to common and 1-way.
The third wire on the landing switch goes to the lamp and the other side
of the lamp goes to neutral.
If that is the case, power will only go to the landing switch common
when the landing switch is in one position. The stairs switch will then
only switch the lamp on when the landing switch is in one position and
the landing switch will only switch the lamp on when the stairs switch
is in one position.
The fault could then be as simple as the black wire has been swapped
with the red wire going to the lamp, at the switch terminals...An easy
thing to happen, if say the switch was taken off for painting and put
back incorrectly.
Of course that is only a possibility. You can't assume that is the case
because, if it isn't and you move the wires, you could put a dead short
across the supply...
What you need is a mains tester - ideally one that doesn't need to make
contact with bare wire to show that it is live. Then remove all the
wires from both switches and find out which wire is live. Connect that
back to the switch, plus one other, and hence find which wire at the far
end is live. Bit by bit, connecting one wire in the switch in addition
to the live at a time, you will be able to identify all the wires and
where they go.

I think we established earlier that the two switches (well, one "way" on
each of the 2 switches) must be in series. It is the only explanation.

Agreed (i.e. a very plausible possibility) as i my post (which doubtless
ovberlapped with yours) - but I emphasise the "symmetry" of the issue. The
inadvertent swapping of a common and (say) L1 could have occured on either
switch - but you wouldn't know which switch (and it doesn't matter which).
Except, as I think I implied, the likely colour scheme (and how strange that
this arises just hours after the "3 core colour scheme" thread!) was
originally the black was used as the common-to-common link.

Most unlikely. You would need a neutral feed to at least one of the
switches, and I can't imagine anyone having done that.

I strongly advise the OP *NOT* to use a tester (even if it doesn't have to
touch live). With no disrespect to the OP, that would require him to work
on the circuit when not isloted - OK for experienced people, but dodgy if
2-way lighting circuits are at all confusing him.
For safety, I much prefer trying a series of permutations - only switching
back on at CU to test the result each time.

I had a long thought about the use of a tester versus simply trying
swapping wires at the switches - hence our posts crossing..
On one hand, there is the risk of working with live wires with a tester.
That is a known and quantifiable risk. As long as the person doing the
work doesn't touch anything and simply moves a tester close to each wire
in turn, the risk is much the same as approaching the edge of a busy
road but not stepping on to it. The person just needs to be very careful
not to trip...
On the other hand, with swapping wires on switches, is the risk that
there may be a neutral there somewhere. For example, live and neutral
could have been brought to the stairs with originally just line
connected to 2way and the neutral left unconnected.. Then someone
painting and decorating found an unconnected wire and a switch with one
terminal with no wire in it... I agree that risk is remote but the
result of swapping wires and then operating the switch could be extreme.
Just as an assumption about no neutral being present could be wrong, so
could an assumption about fault clearance devices, etc, etc.
In view of that, I would rather trust the OP* not to touch any wire,
with the power on, than trust to assumptions about what the rest of the
wiring may, or may not, be..
*Who, to me, came across as someone intelligent and sensible.
YMMV.

Thanks very much for all the advice (and warnings). I'll try what has
been posted and report back.
Two things.
The bedroom is wired as a two way. It might be worth bobbing into the loft
to see if a pull switch has been removed and shoved above the plasterboard.
Secondly, the most obvious thing on the diagram is a wiring fault with the 2
way for upstairs/downstairs switches. The black and red wires that go into
the terminals labeled 1 way and two way should go to the same terminals on
both switches. This is obviously not the case (2 reds at the landing switch
on the 1 way and two way connections). This will probably be a twin and
earth cables to the 1way/2way terminals with the red to the common just
being red and earth
Adam

net>
Firstly Thanks to everyone. Secondly. I've been up and down stairs all
day and am still no nearer finding the solution. I've logged what
happened at each change and just hope one of you brainboxes can work
out what needs to be done - I admit I'm lost! Please see the diagram
(and find it in your heart to help - please!)
Paul
http://peverett.pwp.blueyonder.co.uk/switches.html

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